gcc 14 and modules

gcc 14 and modules

[Wilhelm Meier]

Hi all,

the following test program

import std;
int main() {}

compiled with

/usr/local/bin/g++  -g -std=c++23 -fconcepts -fmodules-ts -O3 -Wall 
-Wextra test400.cc --output test400

gives the following errors:

std: error: failed to read compiled module: No such file or directory
std: note: compiled module file is 'gcm.cache/std.gcm'
std: note: imports must be built before being imported
std: fatal error: returning to the gate for a mechanical issue

The standard library module std should be available, but obviously is not.

Aside from header units: is the a way to create the std module by my own?

Will gcc be shipped with the module std?

Thanks,
  Wilhelm

Re: gcc 14 and modules

[Jonathan Wakely]

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On Tue, 2 May 2023, 13:03 Wilhelm Meier wrote:

> Hi all,
>
> the following test program
>
> import std;
> int main() {}
>
> compiled with
>
> /usr/local/bin/g++  -g -std=c++23 -fconcepts -fmodules-ts -O3 -Wall
> -Wextra test400.cc --output test400
>
> gives the following errors:
>
> std: error: failed to read compiled module: No such file or directory
> std: note: compiled module file is 'gcm.cache/std.gcm'
> std: note: imports must be built before being imported
> std: fatal error: returning to the gate for a mechanical issue
>
> The standard library module std should be available, but obviously is not.
>

Right. Just because you used -std=c++23 doesn't mean the compiler actually
supports all of C++23. It's still a work in progress.



> Aside from header units: is the a way to create the std module by my own?
>

Not very easily.


> Will gcc be shipped with the module std?
>

Eventually, yes, we will provide a std.cc module definition file, which you
will be able to compile and then import.

Re: gcc 14 and modules

[Wilhelm Meier]

On 02.05.23 14:28, Jonathan Wakely wrote:

>     Will gcc be shipped with the module std?
> 
> 
> Eventually, yes, we will provide a std.cc module definition file, which 
> you will be able to compile and then import.

Is it possible to create the std.cc (or sort of) by my own?

Re: gcc 14 and modules

[Jonathan Wakely]

On Tue, 2 May 2023 at 18:47, Wilhelm Meier <wilhelm.meier@hs-kl.de> wrote:
>
> On 02.05.23 14:28, Jonathan Wakely wrote:
>
> >     Will gcc be shipped with the module std?
> >
> >
> > Eventually, yes, we will provide a std.cc module definition file, which
> > you will be able to compile and then import.
>
> Is it possible to create the std.cc (or sort of) by my own?

You need to name pretty much everything from namespace std, and last
time I tried, it either crashed the compiler (see numerous bugs) or
failed to compile (e.g.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102345)

Re: gcc 14 and modules

[Wilhelm Meier]

On 02.05.23 20:09, Jonathan Wakely wrote:
> On Tue, 2 May 2023 at 18:47, Wilhelm Meier <wilhelm.meier@hs-kl.de> wrote:
>>
>> On 02.05.23 14:28, Jonathan Wakely wrote:
>>
>>>      Will gcc be shipped with the module std?
>>>
>>>
>>> Eventually, yes, we will provide a std.cc module definition file, which
>>> you will be able to compile and then import.
>>
>> Is it possible to create the std.cc (or sort of) by my own?
> 
> You need to name pretty much everything from namespace std, and last
> time I tried, it either crashed the compiler (see numerous bugs) or
> failed to compile (e.g.
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102345)

So, for the moment one should stick to import header-units?
But these need to be precompiled: how do I solve the dependency problem, 
e.g. how do I precompile all imported header-unit a source-file mentions?